Core A will provide scientific, budgetary, administrative, logistic, and biostatistical oversight to all aspects of the Program Project. The Core will facilitate communication among investigators and sharing of reagents, tools, specimens, and data;will ensure appropriate allocation of funds to each Project and appropriate use of these funds;will provide clerical support;will coordinate the Projects with subcontracted institutions;will organize regular investigator meetings;and will provide biostatistical assistance. Dr. Bolli, Core Leader, will be responsible for the overall coordination, integration, and administration of the Program Project, for the appropriate utilization of the funds, for compliance with institutional and federal regulations, for the scientific productivity of the Program, and for any issues related to the Program. The Principal Investigator will be assisted by the other members of the Executive Committee, which will be composed of the four Project Leaders and the four Core Leaders. The Principal Investigator and the executive Committee will meet on a monthly basis to discuss the scientific progress, data, problems, and future directions for the four Projects. Scientific responsibilities include (1) providing leadership in maintaining the focus of the investigators, (2) providing statistical assistance, and (3) weekly meetings of all Program Project Investigators. Administrative and financial responsibilities include (1) implementing guidelines for Program Project support, (2) administering the budget according to NIH guidelines, (3) monitoring budgets for each Project and Core, and (4) ensuring compliance with the institutional and NIH regulations. The Biostatistician working in the Core will be Dr. Maiying Kong. She will attend the monthly meetings of the Executive Committee, review the experimental data, analyze them, and calculate group sizes for future studies. She will devote 10% of his/her time to this Program Project. An important aspect of this Program Project is that the investigators performing in vivo studies of CPCs will be blinded to the treatment until the final data analysis is released by Dr. Kong. Another important aspect is that all sample sizes will be selected before the experiments are started (based upon power analysis by Dr. Kong) and will not be changed;the experiments will be carried out until the predetermined sample sizes are achieved, without any knowledge of interim results. After the predetermined sample sizes are achieved, all data will be given to Dr. Kong, where they will be unblinded and analyzed by appropriate statistical methods. Each Project will utilize 25% of Core A.